For example in industrial applications such as controlling robots, in automotive applications such as passenger entainainments systems, or in other entainment applications such as a concert hall or a stadium, a data stream is provided from a source to at least one destination via a communication network. In this respect, the term “data stream” may denote an unidirectional flow of data, for example audio and/or videodata, from the source to one or more destinations. The term “source” may denote an end station which may be a producer of the data stream, and the source can also be denoted as a Talker. The term “desination” may denote an end station which may receive or consume a data stream, and the destination may also be denoted as a Listener.
In the above applications, the source announces a provision of a data stream. Then at least one destination registers for receiving the data stream, and a communication network intermediate the source and the destination ensures the transport of the data stream from the source to the at least one destination while meeting stream requirements concerning for example quality of service and bandwidth. The data stream may be usually time sensitive in that strict time requirements have to be met to properly transport the data stream from the source to the at least one destination. Further, the communication network may be embodied as a bridged network or bridge network in which multiple hops and links are present between respective edge nodes to which the source and destination may be adjacent. It is noted that the terms “bridge network” and “bridged network” can be used in this application in an interchangable way.
The Multiple Stream Reservation Protocol (MSRP) is a protocol designed to provide Quality of Service (QoS) for streams in such a bridged network by means of reserving resources within each bridge along the stream path of the data stream. The MSRP operation is based on exchanging Multiple Stream Registration Protocol Data Units (MSRPDUs). The operation of MSRP is specified by IEEE 802.1Q-2011. A project called IEEE P802.1Qcc is initiated and aims for specifying extensions and enhancements to the Stream Reservation Protocol (SRP), thus for specifying MSRP. Reference for P802.1Qcc Stream Reservation Protocol (SRP) Enhancements and Performance Improvements is made to http://www.ieee802.org/1/pages/802.1cc.html.
Further, Intermediate System to Intermediate System (IS-IS) has been introduced by the IEEE 802.1aq Shortest Path Bridging (SPB) specification for bridge networks. Further IS-IS extensions for a bridge network are currently being specified by an ongoing IEEE 802.1Qca Path Control and Reservation (PCR) project, in order to provide further capabilities, for example capabilities which are beyond a shortest path utilization. Reference for P802.1Qca Path Control and Reservation is made to http://www.ieee802.org/1/pages/802.1ca.html.
Stream Reservation Protocol (SRP) is specified for Rapid Spanning Tree Protocol (RSTP) and Multipe Spanning Tree Protocol (MSTP) networks. Therefore, SRP cannot leverage the capabilities provided by IS-IS, for example shortest path. The latter may be due to the fact that RSTP and MSTP might not support of functionalities of SPB of SRP. Even the interworking of the old Generation 1 SRP and IS-IS is not clearly specified. Further, Generation 2 SRP will have new features, so as IS-IS with the Qca extension, for example the capability of setting up explicit paths which may be not the shortest path thus may provide disjoint paths for the protection of a given stream. The interworking of SRP and IS-IS is a missing piece. A method for this interworking has to be provided, in order to leverage the features provided by IS-IS for time-sensitive streams as well.
To sum up, SRP was specified for bridge networks controlled by RSTP or MSTP. Nevertheless, RSTP and MSTP have some characteristics that are undesirable for the streams, for example RSTP and MSTP do not support an efficient setut-up of a shortest path in a bridge network. Furthermore, the introduction of IS-IS into bridge networks by Shortest Path Bridging (SPB) and the on-going IEEE P802.1Qca Path Control and Reservation (PCR) project open up new possibilities both for the existing SRP and the next version (Generation 2, Gen2) that will be specified by the IEEE P802.1Qcc project. However, a method for interworking between SRP and IS-IS is needed for leveraging the potential capabilities of IS-IS, for example, in a bridge communication network, which method may represent a missing piece.